Screw pump



3 Shees-Sheet l m. V. Y m. m. N HM. 0M N.

J. H. DAVIS SCREW PUMP Aug. 4, 1953 Filed May E28, 1946 J. H. DAVISSCREW PUMP Aug. 4, 1953 3 Sheets-Sheefl 2 Filed May 28, 1946 J. H. DAVISAug. 4, 1953 SCREW PUMP 3 Sheets-Sheet 3 Filed May 28, 1946 @www 062ml.QW

Patented Aug. 4, 1953 SCREW PUMP John H. Davis, Detroit, Mich., assignorto Jessie A. Davis Foundation, Inc., Detroit, Mich., a corporation ofDelaware Application May 28, 1946, Serial No. 672,801

(Cl. S-89) 8 Claims.

This invention is a novel pump, and the principal object thereof is toprovide a pump radically differing in principle from the conventionaltype of pump, my pump having a conical shaped impeller carrying nssurrounded by a sleeve secured thereto and closely fitting the machinedouter edges of the fins which are preferably spirally arranged so thatthe cone and fins and sleeve rotate as a unit and impart to a liquidmedium a velocity longitudinally of the impeller axis while building upa pressure radially from intake to discharge by centrifugal force, suchpressure and velocity being governed by the rotational speed anddiameter of the impeller.

A further object of the invention is to provide a pump of the above typewhich would be simple, novel and eiiicient in operation, and will becapable of delivering .a wide range of fluid capacity by merelyregulating the speed of the impeller or the area of the outlet.

Other minor objects of the invention will be hereinafter set forth.

I will explain the inventionwith reference to the accompanying drawings,which illustrate one practical embodiment thereof to enable othersfamiliar with the art to adopt and use the same; and will summarize inthe claims the novel features of construction, and novel combinations ofparts, for which protection is desired.

In said drawings:

Figure l is a side elevation of my pump.

Fig. 2 is a longitudinal section through the impeller chamber of thepump, also through the impeller mounted therein.

Fig. 3 is an enlarged side elevation of the nose of the pump showing thearrangement of ns therein.

I Fig. 4 is an end View of the nose shown in Fig. 3 looking at thelarger end.

Fig. 5 is an enlarged section through the outer roller bearing for theimpeller shaft.

Fig. 6 is an enlarged section through the inner roller bearing of theimpeller shaft.

As shown in the drawings, the pump comprises an impeller casing I havinga base 2 adapted to be mounted on a xed support. Casing I is providedwith an axial extension Ia at one end in which are mounted theanti-friction bearings of `an impeller shaft 3 carrying on its inner endWithin the casing I a cone head 4, said cone having formed on itsperiphery spiral fins 5, each vof which as shown preferably extendsthrough sired. The head 4 is of conical shape, and such shape ispreferable, but the angularity of the cone may be any desired degree.

As shown, the height of the fins 5 is greater at the smaller end of thecone head 4 than at the large end so that the volume of fluid passingthrough the impeller will remain constant as the cross-sectional area atall points along the cone head axis is the same.

'Ihe conical head 4 is preferably hollow as indicated at 4a, Fig. 2, inorder to save unnecessary weight. As shown, the shaft 3 is provided withsplines 3a adapted to engage corresponding slots in the hub of the conehead. The inner end of the head 4 engages an external annular ange 3b onthe shaft 3 and the cone head 4 is retained on the shaft 3 by means of anut 3c engaging threads at the inner end of the shaft, a washer 3d beinginterposed between the nut 3c and the inner end of the hub of the conehead. Suitable locking means to prevent rotation of the nut may beprovided, such as an Allen head screw 3e tapped into a threaded boreadjacent the periphery of the nut, the nut being split at right anglesnormal to the said screw 3e so that when the screw 3e is tightened thethreaded bore of the nut 3c will be distorted. Other means, however, maybe used.

Around the shaft 3 preferably opposite the enlarged shoulder 3b is anoil seal 6 of conventional type, and shaft 3 is journaled in theextension Ia, of casing I by means of roller bearings 1 and 8erespectively, the inner bearings 'I engaging the annular shoulder 3b(Fig. 6) of shaft 3, and a sleeve 9 being disposed on the shaft 3between the inner races of the bearings 1 and 8e. The outer race ofbearing 8e is mounted in an enlargement I f of bore la as shown in Fig.5, and its outer face is engaged by a cap Il secured by studs, bolts orthe like I8 to the end of casing Ia, a seal or packing I9 (Fig. 5) beingprovided I in the cap Il around shaft 3 to lseal the outer end of thebore Ia around shaft 3. The outer face of the inner race 82 is engagedby a lock nut I6 of conventional type mounted upon a threaded section ofshaft 3. Thus the inner races of the bearings 'l and 8e are fixed withrespect to the shaft 3 so as to prevent axial movement of the shaftwithin the casing.

Within the casing I around the cone head 4 is a sleeve 5a soldered,welded or brazed to the outer peripheries of the fins 5, said sleeve 5afollowing the peripheries of the ns throughout their lengths andterminating at the outer enlarged ends of the fins. Members 4, 5 and 5atogether form the pump impeller. Thus the liquid which enters the intakeend of the impeller will have its velocity and centrifugal forceincreased in its movement towards the discharge end of the impeller, andthe liquid emerging from the outer larger end of the impeller will havea strong swirling motion, while at the same time it is forced axiallyaway from the end of the impeller towards the nose chamber 8 at thedischarge end of the pump casing.

The outer wall im (Fig. 2) of the cone head 4 should be slightly arcuatein form rather than a true conical surface, the flare being outward andgreatest at the center of the length of nuns 5. This permits thecross-sectional area between the head i and the sleeve 5a, to remainconstant.

rIhe casing l surrounds the .sleeve :5c vand .is spaced therefrom, andwithin the portion oppo site the inner end of the sleeve 5a is anannular ring lil which is substantially V-shaped in crosssectien withits apex disposed adjacent the :beveled .inner end "5b of `the sleeveha, thus providing a very slight .clearance lea between the :ring m andthe inner end 4of the sleeve. The clearance between the ape-X and theinner end .Eb of sleeve .5a is for the purpose of preventing .any.extraneous mattei' except the finest sand passing 'through theclearance space ida between the ring l0 and sleeve 5a. It will be notedhowever that the clearance between the casing l and :the inner .end .ofthe sleeve 5a progressively .decreases .towards :theouter end of thesleeve, said difference in clearance permitting sand, grit or othersediment which lmay be passed through the .clearance .lita to .be.carried out along with the 'liquid passing through said .clearancespace lsb :at the outer .end .of thesleeve 15a, the movement .of liquid.axially .through the impeller creating .a suction in theclearance space.ith sufcient to maintain the same lclear of sediment, said suc-'tionzpulling `the sedimenti/o and beyond the outer end .of sleeve 5a.and into Lthe nose chamber 8 hereinafter described.

Inthe :casing I .around the shaft 3 andopposite the inlet .end of theimpeller is Aan inlet chamber H., the end .of which .communicatesdirectly with the .space between the cone -head 4 and the sleeve 5a.Inlet chamber .ll is 4fed .by one, :two .or more yinlet pipes I2, twobeing indicated in Fig. :2, `.whereby .a substantial iiow of water isconstantly maintained at :the "inlet .end Q the impeller to be passed`therethrough into the .nose chamber :8.

.As shown Fig. 1, the -nose member 8 is se- .cured :to the l.outlet endof casing I .by means vof `bolts 8a, fsaid .nose .chamber 8 .beingsubstantially cylindrical ladjacent the impeller .and reducing indiameter towards the outlet `.end 8d. `Within ythe nose chamber 18 is .a`core Bb Isubstantially ipa-rallel with the .inner wallof the nose.chamber 8 throughout the major portion of .its length but contractingtowards the -outlet end to sub.. -stantially a point '80, in ordertokeep the amount 'of fluid passing through the nose chamber 3substantially .constant throughout the length thereof due to thedecrease in diameter towards the outlet Tend -tdof the nose chamber 8.`Said .core .-819 is designed to .'iill the otherwise vacuum cone whichwould be created by "the flow of whirling waterdischarged from theimpeller into the `nose chamber '8. Between the core .3b and the innerwall ,of the nose chamber l8 is an an- ;nular.series :of fins 8c, threeybeing indicated .in iiigil` which as showniin Fig. v3 areysubstar-ltially `coaxial.with1the;;nose chamber 8 :fremithe .outer 75end 8c to approximately one-half the length back through the nosechamber, at which point the ns are formed arcuately to substantially theshape of the reverse curve of the outer ends of the fins 5, the purposeof the iins 8c being to stop whirling of the volume of water dischargedinto the nose chamber from the impeller and to cause the ilow of waterin the nose chamber to be in a straight line direction.- "The fins 8eare an important part of my invention, for it has been found in practicethat without the fins the volume of water delivered by the pump issubstantially infinitesimal as the tendency of the water Adischargedfrom the impeller is to pass in a radial direction tangent to the outerend of the impel'ler. 'The volume of water, however, upon ,striking thefins 8e is caused to move in a straight line towards the outlet Sd ofthe nose chamber.

In operation, the pump shaft 3 is driven in the .direction of the arrows3m, Fig. 2, by .any suitable prime mover. 'The liquid to be Dumped issupplied through the inlet pipes t2 to .the inlet .chamber il, .the pumpbeing previously primed. As the l.shaft s rotates, the impeller 1.6, 5and .5a rotates therewith. The rapid. increase diameter of .the impeller.-cone 4, combined @with the high pitch of the spiral ns `5 will .causethe pressure .of the liquid rwithin the vimpelfler to gradually build:up parallel to .the impelier axis, forcing the liquid r'along vtheimpeller .4, 5, r5ga through Ithe fins .5 .while .building :up a highpressure radially due to centrifugal force, which pressure reacts uponthe conical sleeve 15a .to exert an axialcomponent whereby assthe liquid.emerges vvarying :the speed of .rotation of :the impeller,

or by valve means (not shown) :applied to Ytglie .discharge .end 8d. Mypump 'will ,have la .wide

range of capacity depending 11110.11 :the adjustment of `the :valveAmeans,:whereby the pumpmay be continued to be run at full :Speed rwhiledelivering ,only .-a ,small Qapaty Withoill? zlillly thereto asno fbackpressure built up therein to injlile fthe ,pump. 1This feature is van-i-mportant improvement .over conventional ,pumps .designed for only one'capacity and which `must he driven .at the 'designed speed to deliversuch capacity, for in my pump as the valve means is closedthe .power torotate the dispel-1er at the same speed becomes "les rather l.thangreater, as in Lconventional pumps.

I do not limit :my invention to-the .exact forms shown inthe drawings,for obviously changesfmay be made therein `-within the :scopeof theclaims.

I claim: p

1. A liquidpump, comprising an impeller chamber contracting towards oneend into an inlet; a nose chamber of greater length than the -impellerchamber connected to thelarger end offthe impeller chamber yandcontracting :towards its outer end into an outlet; `a driven .shaftentering :the inlet -end of the f-impellerfchamber coaxially thereof;kan impeller :on .said shaft within .the

Vimpeller chamber land comprising a ,substantially cone-shaped .headenlarging itQWaIds 'the nose chamber, a series l.of spirally arrangeddus on -said vcone head having aV 'steep pitch, said fins fbeing spacedfrom the walls of the impeller chamber, and a' sleeve` surmounting thefins and rotatable with the head, said sleeve having a slight posed coretherein whose outer surface is substantially parallel with the innerwall of the nose v chamber throughout -the major portion of its lengththereby maintaining the area between the Score and nose chambersubstantially constant throughout its length, and said nose chamberhaving fixed axially disposed ns between its innerwall and the surfaceof the core adapted to convert the rotary motion of the liquid emergingfrom the impeller into rectilinear motion 'within the nose chamberbefore emerging from -the outlet, the area between adjacent fins and"the head and sleeve of the impeller remaining substantially constantthroughout the `length of the head, to maintain a constant volume ofliquid rpassing through the impeller.

2. A liquid pump, comprising an impeller chamber contracting towards oneend into an inlet; a nose chamber 0f greater length than the impellerchamberV connected to the larger end of the impeller chamber andcontracting towards its outer end into an outlet; a driven shaftentering the inlet end of the impeller chamber coaxially thereof; animpeller on said shaft within the impeller chamber and comprising asubstantially coneshaped head enlarging towards the nose chamber, aiseries of spirally arranged fins on said cone head having a steep pitch,said fins being spaced from the walls of the impeller chamber, and alsleeve surmounting the fins and rotatable with the head, said sleevehaving a slight'clearance from the walls of the impeller chamber; thespace 'between the head and sleeve progressively decreasing toward thelarger end 0f the impeller; an inlet port at the inlet communicatingwith "the smaller end of the impeller and having a feed openingcommunicating therewith; and said no se chamber having an axiallydisposed core therein whose outer surface is substantially parallel with`the inner wall of the nose chamberthroughout the major portion of itslength thereby maintaining the area between the core and nose chambersubstantially constant throughout its length, and

said nose chamber having fixed axially disposed 'fins between its innerwall and the surface of the core adapted to convert the rotary motion ofthe liquid emerging from the impeller into rec- -tilinear motion withinthe nose chamber before emerging from the outlet, said impeller finseach making a half turn throughout the length of the head; and the area'between adjacent fins and lthe head and sleeve of the impellerremaining substantially constant throughout the length of the head, tomaintain aconstant volume of liquid `passing through the impeller.

3. A liquid pump, comprising an impeller cham- Lvber contracting towardsone end into an inlet; a nose chamber of greater length than theimpeller i chamber connected to the larger end of the irnpell'er chamberand contracting towards its outer 'end into an outlet; a driven shaftentering the inlet end of the impeller chamber coaxially thereof;` animpeller on said shaft within the impeller chamber and comprising asubstantially 'coneshaped head enlarging towards the nose chamber, `aseries of spirally arranged fins on said cone head having a steep pitch,said fins being spaced from the walls of the impeller chamber, and asleeve surmounting the fins and rotatable with the head, said sleevehaving a slight clearance from the walls of the impeller chamber; thespace between the head and sleeve progressively decreasing toward thelarger end of the impeller; an inlet port at the inlet communicatingwith the smaller end of the impeller and having a feed openingcommunicating therewith; and said nose chamber `having an axiallydisposed core therein whose outer surface is substantially parallel withthe inner wall of the nose chamber throughout the major portion of itslength thereby maintaining the area between the core and nose chambersubstantially constant throughout its length, and said nose chamberhaving xed axially disposed fins between its inner wall and the surfaceof the core adapted to convert the rotary motion of the liquid emergingfrom the impeller into rectilinear motion within the nose chamber beforeemerging from the outlet, the inner end of the sleeve being beveled; anda ring of substantially correspondingly shaped cross-section disposed inthe impeller chamber with its apex adjacent the beveled end of thesleeve while providing a slight clearance between the sleeve and ring;and the vclearance between the sleeve and walls of the rimpeller chamberprogressively decreasing towards the outer end of the sleeve, wherebyduring op-eration of the pump suction created between the outer end ofthe sleeve and wall of the impeller chamber will maintain the spacebetween the sleeve and wall of the impeller chamber free from sediment.

4. A liquid pump, comprising an impeller chamber contracting towards oneend into an inlet; a

ynose chamber of greater length than the impeller chamber connected tothe larger end of the impeller chamber and contracting towards its outerVend into an outlet; a driven shaft entering the inlet end of theimpeller chamber coaxially thereof; an impeller on said shaft within theimpeller chamber and comprising a substantially coneshaped headenlarging towards the nose chamber,

-a series of spirally arranged ns on said cone Shead having a steeppitch, said fins being spaced .from the walls of the impeller chamber,and a sleeve surmounting the fins and rotatable with the head, saidsleeve having a slight clearance from the walls of the .impellerchamber; the space between the head and sleeve progressively decreasingtoward the larger end of the impeller; an inlet port at the inletcommunicating with the smaller end of the impeller and having a feedopening communicating therewith; and said nose chamber having an axiallydisposed core therein whose outer surface is substantially parallel withthe inner wall of the nose chamber throughout the major portion of itslength thereby maintaining the area between the core and nose chambersubstantially constant throughout its length, and said nose chamberhaving fixed axially disposed ns between its inner wall and the surfaceof the core adapted to convert the rotary motion of the liquid emergingfrom the impeller into rectilinear motion within the nose chamber beforeemerging from the outlet, the walls of said head being flared outwardly,and said fiare being greatest at Athe center of its length.

5. A liquid pump, comprising an impeller chamber contracting towards oneend into an inlet; a nose chamber of greater length than the impellerchamber connected to the larger end of the impeller chamber andcontracting towards its outer end into an outlet; a driven shaftentering the inlet end of the impeller chamber coaxiall'y thereof; animpeller on said shaft within the impeller chamber and comprising asubstantially coneshaped head enlarging towards the nose chamber andterminating adjacent the outer end of said impeller chamber, a series ofspirally arranged iins on said cone head having a steep pitch, said nsbeing spaced from the wallsk of the impeller chamber, Iand a sleevesurmounting the ns and rotatable with the head, said sleeve embracingthe length of the head, said sleeve having a slight clearance trom thewalls of the impeller chamber;

the space between the head and sleeve progressively decreasing towardthe larger end, of the impeller; an inlet port disposed around the sh ftand communicating with the smaller end of the impeller and hav-ing aninlet opening communieating therewith; and said nose chamber having anaxially disposed core therein whose outer surface is substantiallyparallel with. the inner wall of the nose chamber throughout the majorportion of its length thereby maintaining the area between the core andnose chamber substantially constant throughout its length, and said nosechamber having xed axially disposed iins between its inner wall and thesurface of the core adapted to convert the rotary motion of the liquidemerging from the impeller into rectilinear motion within the nosechamber before emerging from the outlet, the areal between adjacent nsand the head and sleeve or" the impeller remaining substantiallyconstant throughout the length of the head, to maintain a constantvolume of liquid pass-ing through the impeller.

6; A liquid pump, comprising an impeller chamber contracting towards oneend into an inlet; a

nose chamber of greater length than the impeller' L chamber connected tothe larger end of the impeller chamber and contracting towards its outerend into an outlet; a driven shaft entering the inlet end of theimpeller chamber coaXially thereci; an impeller on said shaft within theimpeller chamber and comprising a substantially coneshaped headenlarging towards thev nose chamber and terminating adjacent the outerend of said impeller chamber, a series of spirally arranged fins on saidcone head having a steep pitch, said fins being spaced from the walls ofthe impeller chamber, 'and a sleeve surmounting the ns and rotatablewith the head, said sleeve embracing the length of the head, sairlsleeve having a slight clearance from the walls of the impeller chamber;the space between the head and sleeve progressively decreasing towardthe larger end ci' the impeller; an inlet port disposed around the shaftand communicating with the smaller end of the impeller and having aninlet opening communieating therewith; and said nose chamber having anaxially disposed core therein whose outer surface is substantiallyyparallel with the inner wall of the nose chamber throughout the majorportion of its length thereby maintaining the area between the core andnose chamber substantially constant throughout its length, and said nosechamber having fixed axially disposed fins between its inner wall andthe surface of the core adapted to convert the rotary motion of theliquid emerging from the impeller into rectilinear motion within thenose chamber before emerging from the outlet, said impeller hns eachmaking a half turn throughout the length of the head; and 'the areabetween adjacent ns and the head and sleeve of the impeller remainingsubstantially constant throughout thelength of the head, to maintain aconstant volume of liquid passing through the impeller.

'7. A liquid pump, comprising animpeller chamber contracting towards oneend into an inlet; a nose chamber of greater length than the impellerchamber connected to the larger end of the imheller chamber andcontracting towards its outer end into an outlet; a drivenishaftentering the inlet end of the impeller chamber coaxially thereof; animpeller on said shaft within the impeller chamber and comprising: asubstantially coneshaped head enlarging towards the nose chamber andterminating adjacent the outer. end of said impeller chamber, a seriesof spirally arranged uns on said cone head having a steep pitch, said nsbeing spaced from the walls of the impeller chamber, and a sleevesurmounting the iins and rotatable with the head, said sleeve embracingthe length of the head, said sleeve having a slight clearance from thewalls of the impeller chamber; the space between the head and sleeveprogressively decreasing toward the larger end of the impeller; an inletport disposed around theshaft and communicating with the smaller end ofthe impeller and having an inlet opening communieating therewith; andsaidnose chamber having an axially disposed core therein whose outersurface is substantially parallel with the inner wall of the nosechamber throughout the major portion o its length thereby maintainingthearea between the core and nose chamber substantially constantthroughout its length, and said nose chamber having fixed axiallydisposed fins between its inner wall and the surface of the core adaptedto convert the rotary motion of the liquid emerging from the impellerinto rectilinear motion within the nose chamber before emerging fromther outlet, the inner end of the sleeve being beveled; and a ringofsubstantially correspondingly shaped cross-section disposed in theimpeller chamber with its apex adjacent the beveled end yof the sleevewhile providing a slight clearance between the sleeve and ring; and theclearance between thesleeve and walls of. the impeller chamberprogressively decreasing towards the .outer end ofthe sleeve, wherebyduring operation of the pump suction createdv between the vouter end ofthe sleeve and wall of the impeller chamber will maintain the spacebetween the sleeve and. wall ci the impeller chamber free from sediment.

8. A liuuid pump, comprising an impeller chamber contracting towards oneend into an inlet; a nose chamber of greater length than the impellerchamber connected to. the larger end of the impeller chamber andcontracting towards its outer end into an outlet; a driven shaftentering the inlet end of the impeller chamber coaXially thereof; animpeller on said shaft within the impeller chamber and comprising asubstantially coneshaped head enlarging towards the nose chamber andterminating adjacent the outer end of said impeller chamber, a series ofspirally arranged hns on said cone head vhaving a steep pitch, said nsbeing spaced from the walls of the impeller chamber, and a sleevesurmounting the hns and rotatable with the head, said sleeve embracingthelength of the head, said sleeve having a slight clearance from thewalls of the impeller chamber; the space between the head and sleeveprogressively decreasing toward the larger end of the impeller; an inletport disposed around the shaft and communicating with the smaller end ofthe impeller and hav-ing an inlet opening communieating therewith; andsaid nose chamber having an axially disposed core therein Whose outersurface is substantially parallel with the inner wall of the nosechamber throughout the major portion of its length thereby maintainingthe area between the core and nose chamber substantially constantthroughout its length, and said nose chamber having fixed axiallydisposed ns between its inner wall and the surface of the core adaptedto convert the rotary motion of the liquid emerging from the -mpellerinto rectilinear motion Within the nose chamber before emerging from theoutlet, the walls of said head being flared outwardly, and said are-being greatest at the center of its length.

JOHN H. DAVIS.

References Cited in the le of this patent UNITED STATES PATENTS NumberNumber Name Date Magnot June 21, 1898 Freid Jan. 10, 1905 Angus Sept.26, 1922 Lawaczeck Dec. 16, 1930 FOREIGN PATENTS Country Date Germany1906 Great Britain Aug. 26, 1926 Great Britain Feb. 8, 1939

